cterrebonne
God
Looking to start tearing into the V20. Would one layer of 1708 mesh over the stringers would be enough? Or should I do two layers? I am open to ideas. I will being going with epoxy resin.
1708 mat for stringers
- Thread starter cterrebonne
- Start date
tartuffe
Junior Member
The 1708 is primarily used with polyester resins. The mat sucks up so much resin that is makes for a good waterproofer but it is not as strong as the biax. The problem is that it sucks up so much resin.
When you use epoxy, it is a much better waterproofer ounce for ounce versus polyester so you do not need the mat. Straight 17 oz. biax will be sufficient but personally I am using 2 layers. I like overkill when it comes to my boat. The wood is your structure. The cloth seals the wood. I only go with 2 layers for the purpose of added protection against rubbing over time.
I like US Composites for epoxy and boat builder central for mat.
When you use epoxy, it is a much better waterproofer ounce for ounce versus polyester so you do not need the mat. Straight 17 oz. biax will be sufficient but personally I am using 2 layers. I like overkill when it comes to my boat. The wood is your structure. The cloth seals the wood. I only go with 2 layers for the purpose of added protection against rubbing over time.
I like US Composites for epoxy and boat builder central for mat.
cterrebonne
God
thanks for the info. I was going to use epoxy usa for the resin. Have you heard any negatives about their product?
Also I am looking at the mat. 17 oz 45/45 or 0/90 I see that one mas the chopped strand attached to it is the 45/45.
tartuffe
Junior Member
I am not familiar with epoxy USA. That doesn't mean its not as good, I just liked US Composites pricing. I want to say it is around $340 with shipping to NC for a 7.5 gal kit. It comes in 1 gallon containers. You'll want to start with at least 7 gallons so if their prices at that quantity match up then I would go for it. You'll also want the slowest cure available. I was fortunate that most of my big layups took place when it was 40 degrees outside so that gave me the time to work for several hours on a single batch. Now that it has warmed up I am having to mix smaller batches and it is more challenging.
I like the 45/45 and was advised that is the way to go from the fellas on boat design.net.
Here is another tip that I have learned, MEK costs more than acetone per gallon but you save overall because it does not evaporate nearly as quickly but still quickly
I like the 45/45 and was advised that is the way to go from the fellas on boat design.net.
Here is another tip that I have learned, MEK costs more than acetone per gallon but you save overall because it does not evaporate nearly as quickly but still quickly
cterrebonne
God
thanks for the tips. The epoxy I saw was about 500 for 7.5 gals. It said that it was a no blush formula. I didn't see if the US comp stuff was low/no blush. No big deal if it blushes some simple green can take care of that between coats. The US comp stuff is looking better on price.
What repairs you made that used up 7.5 gallons?
What repairs you made that used up 7.5 gallons?
tartuffe
Junior Member
The U.S. Composites is non blushing if you use their slowest hardener. The middle and quick cure are both blushing.
I'm up to 17 gallons used at this point. The transom used up a good portion. I left about a 2" gap between the wood core and gunnels/hull all the way around the transom to be sure to get it packed full of PB. In hindsight I could have gotten by with a thumbs width. That would have resulted in 2.7 gallons less epoxy. I also used a large amount on the stringers. I bedded those in PB rather than use the foam. That would have saved another 1.25 gallons. Same with the front bulkhead. Also used around 1 gallon used on fairing compound. If you don't need any fairing then you can eliminate that as well.
Oh yeah, I wasted about a gallon when I got ahead of myself and it kicked off so all told I'm up to around 5 gallons of over expense, or education whichever term you prefer.
At this point for new transom, stringers, bulkheads, reinforcement, and floors for storage compartments I'm up to 5 sheets of 3/4 marine grade fir. 21 gallons of epoxy and 50 yards of 17 oz mat at 50" width. Around 2.5 gallons of 1/4 chopped strand, 4 gallons of cabosil, and 1 BILLION 4.5" 24 grit sanding disks. My boat was toast.
Do not add up the costs. Just start it and build as you can afford. As you probably know, working on the boat is half the fun!
I'm up to 17 gallons used at this point. The transom used up a good portion. I left about a 2" gap between the wood core and gunnels/hull all the way around the transom to be sure to get it packed full of PB. In hindsight I could have gotten by with a thumbs width. That would have resulted in 2.7 gallons less epoxy. I also used a large amount on the stringers. I bedded those in PB rather than use the foam. That would have saved another 1.25 gallons. Same with the front bulkhead. Also used around 1 gallon used on fairing compound. If you don't need any fairing then you can eliminate that as well.
Oh yeah, I wasted about a gallon when I got ahead of myself and it kicked off so all told I'm up to around 5 gallons of over expense, or education whichever term you prefer.
At this point for new transom, stringers, bulkheads, reinforcement, and floors for storage compartments I'm up to 5 sheets of 3/4 marine grade fir. 21 gallons of epoxy and 50 yards of 17 oz mat at 50" width. Around 2.5 gallons of 1/4 chopped strand, 4 gallons of cabosil, and 1 BILLION 4.5" 24 grit sanding disks. My boat was toast.
Do not add up the costs. Just start it and build as you can afford. As you probably know, working on the boat is half the fun!
cterrebonne
God
I'm really thrilled to see that you're going to get cracking on the V. I'm really looking forward to seeing your progress on the old girl.
Thanks man, I am thrilled too. It is tough not having a boat to go fishing, lol. I still need to check out your new boat. From the pictures it looks like one sweet rig.
cterrebonne
God
Sounds like your hull needed some work. Mine is in really good shape. Just the transom and the stringers are probably needing to be redone towards the transom area.
Did you separate the liners on your boat? I am thinking about just cutting the floor out and then reglassing it back in and sanding all the old wellcraft factory non skid off and putting down some duraback or some gatorhyde.
cterrebonne
God
hate to bring up an old thread, but I have an epoxy question. From what I have read, if the epoxy does not blush then you can put another coat right over the first one with out sanding? Similar to polyester resin with out wax in it?
I know epoxy is stronger but I made the mistake by calling my local fiberglass repair shop and he said just to use poly. He said if I was worried about water seeping in to just paint it or gel it after? Poly is like half the price, Decisions decisions. I might just split the difference and go with vinylester
I know epoxy is stronger but I made the mistake by calling my local fiberglass repair shop and he said just to use poly. He said if I was worried about water seeping in to just paint it or gel it after? Poly is like half the price, Decisions decisions. I might just split the difference and go with vinylester
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RidgeRunner
God
PE or VE will work but you do have to grind before and in between layers if you let it kick. Wet on wet allows proper bonding and cuts down on grinding. Not as good of a bond as epoxy so the 40 grit scuff marks during prep give the VE/PE something to bind to. PE/VE stinks to high heaven too unlike the epoxy. Neighbors might not like it.. Get a nice industrial fan, and stay upwind.. When it gets hot out, mixing the correct ratio of MEKP to resin gets tricky, a couple extra drops in you mix bucket and you will be fighting to get it rolled out before it kick$$. Epoxy is expensive, but it has distinct advantages.
I think 2 layers of 1708 on the stringers is ample. I am itching to get some glass work started myself. Keep us posted, im excited for you.
I think 2 layers of 1708 on the stringers is ample. I am itching to get some glass work started myself. Keep us posted, im excited for you.
Kracker Jack
God
I tabbed my stringers in with 1708 10 inches into the hull and wrapped it over the stringer and tabbed it 10 inches up the hull on the other side. For checking purposes I then put a second layer over the stringer clears and down the stringer 4 or 5 inches and my stringers do not move at all! Not even a snap or a crack when I purposely tried to move them before my sole was installed. It saved me on some cloth. I went with polyester because I'm new to this and I'm on a serious budget. If I were you I would go with a VE, it is perfectly exceptable for your application and you will save some change in the long run. Just my opinion.
tartuffe
Junior Member
The hull itself is in very good shape. The bulk of my repairs are related to the transom and stringers. I did separate the liner from the hull.
I did add a few layers of glass in high stress areas in the bow area just for the sake of making me feel better.
cterrebonne
God
Tartuffe, after reading this post again you said a single layer of biax would work? I'm trying not to overkill and add too much weight
tartuffe
Junior Member
You can use a single layer of 1708 which includes a layer of CSM stiched in. Biax by itself will not waterproof your wood if you are using VE or PE. Keep in mind that is only on the wrap from your sides and top.
You will need several layers of 17 oz biax like Kracker described when you tab your stringers to the hull.
cterrebonne
God
I'm going to use epoxy. When you say tab, what do you mean. As in 6 inch strips where the stringer and hull meet?
tartuffe
Junior Member
Thats right. I went overboard and cut strips 4", 8", 10" and 12" but that was way overboard. You'll cut your stringers to size, I used spacers (my center bulkheads and barclamps to get my stringers the right distance apart as well as perfectly perpendicular and situated the stringers so everything lined up with all my measurements and marks I made prior to demolition. Once everything lined up inside the boat I traced the inside and outside of the stringers with a sharpie on the hull. Then I raised the whole assembly enough to put a thumb-sized bead of PB between the lines I traced under one stringer. Lowered it all back down on the bead. This gives you good contact and no hard spots. Take more PB and run a small bead on the inside and outside of the stringer and use a sponn to make a nice radius. Lay your first tab and wet it out. If its 6" wide then 3" on the hull and 3" on the stringer. Lay another over top of that one say 10" wide with 5" on the hull and 5" on the stringer. You can do another if you want but probably not necessary but I'm no marine engineer. Like I said, I did 4. Let that cure. Then repeat for the other.
The idea is that you want the fiberglass to dissipate shock loads from the immovable area (stringer) out to the very flexible area of fiberglass without any focus of forces leading to stress cracks.
Keep in mind the best results are to not allow the PB to harden before you get the fabric laid and wetted. Use the slow cure and mix many small batches. I large will cure in about 15 minutes even if it is slow cure.
The idea is that you want the fiberglass to dissipate shock loads from the immovable area (stringer) out to the very flexible area of fiberglass without any focus of forces leading to stress cracks.
Keep in mind the best results are to not allow the PB to harden before you get the fabric laid and wetted. Use the slow cure and mix many small batches. I large will cure in about 15 minutes even if it is slow cure.
cterrebonne
God
Thanks, really good info. I was plannig on going with the foam or 5200. As he bedding. That would give me as long as I needed. Unless you think the woody mix is much better
tartuffe
Junior Member
The foam is probably just as good but I would tab with the full 4 layers if you go that route. The PB is a mix of cabosil and resin. It isn't the wood flour.
Some people get all frothy mouthed about using 5200 versus foam versus PB for bedding. I read an awful lot and personally liked the PB bedding the most. They all have positives.
4 layers of biax is about 1/8" thick so you may have 1/4" of glass supporting your stringer. I figured if I'm buying high dollar 3/4" marine ply, I wanted the full strength transfer throughout my hull.
Some people get all frothy mouthed about using 5200 versus foam versus PB for bedding. I read an awful lot and personally liked the PB bedding the most. They all have positives.
4 layers of biax is about 1/8" thick so you may have 1/4" of glass supporting your stringer. I figured if I'm buying high dollar 3/4" marine ply, I wanted the full strength transfer throughout my hull.
